The Obama administration would not support a nationwide temporary freeze on home foreclosures, said a senior adviser to President Barack Obama.

The adviser, David Axelrod, said Sunday on CBS's "Face the Nation" program that, while faulty paperwork that prompted many banks to put foreclosures on hold has "thrown a lot of uncertainty into the housing market that is already fragile," the administration would not support a nationwide moratorium.

Attorneys general in about 40 states may announce as early as this week a joint investigation into potentially faulty foreclosures at the largest banks and mortgage firms, Bloomberg News reported Friday, citing a person with direct knowledge of the matter. The investigation may center on claims that employees at home lenders and loan servicers signed court documents without ensuring the information was accurate.

"There are in fact valid foreclosures that probably should go forward, where the documentation and paperwork is proper," Axelrod said. The White House is urging the industry to get the problem "unwound very, very quickly," he said.